Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2014	Mar. 19, 2015	Jun. 27, 2014
Document and Entity Information
Entity Registrant Name	Vericel Corp
Entity Central Index Key	0000887359
Document Type	10-K
Document Period End Date	Dec. 31, 2014
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 28,488,020
Entity Common Stock, Shares Outstanding		23,785,653
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash	$ 30,343	$ 8,059
Accounts receivable (net of $40 allowance for doubtful accounts as of December 31, 2014)	8,191	8
Inventory	1,920
Other current assets	1,036	409
Total current assets	41,490	8,476
Property and equipment, net	2,892	739
Intangible assets	3,197
Total assets	47,579	9,215
Current liabilities:
Accounts payable	5,824	2,676
Accrued expenses	4,714	620
Warrant liabilities	1,081	2,019
Other	210	6
Total current liabilities	11,829	5,321
Long term liabilities	109
COMMITMENTS AND CONTINGENCIES (Note 14)
Shareholders' equity:
Common stock, no par value; shares authorized - 75,000 and 15,000; shares issued and outstanding 23,786 and 4,723, respectively	305,008	253,270
Other comprehensive loss	(71)
Accumulated deficit	(307,685)	(287,765)
Total shareholders' equity	35,641	3,894
Total liabilities and shareholders' equity	47,579	9,215
Series B-2 voting convertible preferred stock
Shareholders' equity:
Series B-2 voting convertible preferred stock, no par value: shares authorized and reserved - 39, shares issued and outstanding - 12	$ 38,389	$ 38,389

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts	$ 40
Par value of common stock (in dollars per share)	$ 0	$ 0
Common Stock, shares authorized	75,000,000	15,000,000
Common Stock, shares issued	23,786,000	4,723,000
Common Stock, shares outstanding	23,785,000	4,723,000
Series B-2 voting convertible preferred stock
Par value of convertible preferred stock (in dollars per share)	$ 0	$ 0
Convertible preferred stock, shares authorized	39,000	39,000
Convertible preferred stock, shares reserved	39,000	39,000
Convertible preferred stock, shares issued	12,000	12,000
Convertible preferred stock, shares outstanding	12,000	12,000

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Product sales	$ 28,796	$ 19	$ 21
Total revenues	28,796	19	21
Costs and expenses:
Cost of product sales	17,293	4	6
Gross profit	11,503	15	15
Research and development	21,263	15,104	26,025
Selling, general and administrative	13,774	5,875	7,750
Total operating expenses	35,037	20,979	33,775
Loss from operations	(23,534)	(20,964)	(33,760)
Other income (expense):
(Increase) decrease in fair value of warrants	(27)	5,337	4,248
Bargain purchase gain	3,473
Foreign currency translation gain	152
Interest income	24	16	50
Other expense	(2)
Interest expense	(6)	(11)	(12)
Total other income (expense)	3,614	5,342	4,286
Net loss	$ (19,920)	$ (15,622)	$ (29,474)
Net loss per share attributable to common shareholders (Basic and Diluted) (see note 9) (in dollars per share)	$ (2.23)	$ (6.95)	$ (16.25)
Weighted average number of common shares outstanding (Basic and Diluted)	11,642	3,016	2,060

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (DEFICIT) (USD $) In Thousands, except Share data, unless otherwise specified	Series B-2 voting convertible preferred stock Preferred Stock	Preferred Stock	Common Stock	Accumulated Other Comprehensive Loss	Deficit Accumulated During the Development Stage	Total
BALANCE at Dec. 31, 2012			$ 243,215		$ (275,315)	$ (32,100)
Increase (Decrease) in Shareholders' Equity
Net loss					(15,622)	(15,622)
Net loss						(20,974)
Compensation expense related to stock options granted			926			926
Reclassification of Series B-2 Preferred Stock to equity	38,389				3,224	41,613
Reclassification of Series B-2 Preferred Stock to equity (in shares)	12,000
Reverse stock split common stock in lieu of fractional shares			52		(52)
Reverse stock split common stock in lieu of fractional shares (in shares)			14,000
Exercise of stock purchase warrants			1,983			1,983
Exercise of stock purchase warrants (in shares)			367,000
Issuance of common stock, net of issuance costs of $3,167 and $980 for 2014 and 2013, respectively			7,094			7,094
Issuance of common stock, net of issuance costs of $3,167 and $980 for 2014 and 2013, respectively (in shares)			2,153,000
BALANCE at Dec. 31, 2013		38,389	253,270		(287,765)	3,894
BALANCE (in shares) at Dec. 31, 2013		12,000	4,723,000
Increase (Decrease) in Shareholders' Equity
Net loss					(19,920)	(19,920)
Net loss						(25,925)
Accumulated Other Comprehensive Income (Loss), Net of Tax						(71)
Compensation expense related to stock options granted			839			839
Exercise of stock purchase warrants			2,490			2,490
Exercise of stock purchase warrants (in shares)			408,000
Issuance of common stock, net of issuance costs of $3,167 and $980 for 2014 and 2013, respectively			48,409			48,409
Issuance of common stock, net of issuance costs of $3,167 and $980 for 2014 and 2013, respectively (in shares)			18,655,000
Foreign currency translation adjustment				(71)		(71)
BALANCE at Dec. 31, 2014		$ 38,389	$ 305,008	$ (71)	$ (307,685)	$ 35,641
BALANCE (in shares) at Dec. 31, 2014		12,000	23,786,000

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (19,920)	$ (15,622)	$ (29,474)
Other comprehensive loss
Foreign currency translation adjustment	(71)
Comprehensive loss	$ (19,991)	$ (15,622)	$ (29,474)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities:
Net loss	$ (19,920)	$ (15,622)	$ (29,474)
Adjustments to reconcile net loss to net cash used for operating activities:
Depreciation and amortization	752	489	649
Stock compensation expense	839	926	3,610
Change in fair value of warrants	27	(5,337)	(4,248)
Bargain purchase gain	(3,473)
Foreign currency translation gain	(152)
Loss on sale of fixed assets	139
Write down of retirement asset obligation	(1,102)
Changes in operating assets and liabilities:
Inventory	119
Accounts receivable	(8,139)
Other current assets	(455)	(65)	293
Accounts payable	2,773	(571)	284
Accrued expenses	3,007	237	(659)
Other liabilities	175
Net cash used for operating activities	(25,410)	(19,943)	(29,545)
Investing activities:
Acquisition of CTRM business, net of cash acquired	(1,450)
Property and equipment purchases	(829)	(40)	(273)
Other	101
Net cash used for investing activities	(2,178)	(40)	(273)
Financing activities:
Net proceeds from issuance of common stock and warrants			37,620
Net proceeds from issuance of preferred stock	49,934	14,438	346
Payments on long-term debt	(8)	(34)	(40)
Net cash provided by financing activities	49,926	14,404	37,926
Effect of exchange rate changes on cash	(54)
Net increase (decrease) in cash	22,284	(5,579)	8,108
Cash at beginning of period	8,059	13,638	5,530
Cash at end of period	30,343	8,059	13,638
Supplemental cash flow information (non-cash):
Accretion of convertible preferred stock		1,263	3,993
Warrants exchanged for common stock	965		10,382
Additions to equipment in process included in accounts payable	199
Equipment acquired under capital lease	$ 153

Organization	12 Months Ended
Organization	Dec. 31, 2014
Organization
Organization	1.Organization Vericel Corporation (the Company or Vericel, which was formerly known as Aastrom Biosciences, Inc.) was incorporated in March 1989 and began employee-based operations in 1991. On May 30, 2014, Vericel completed the acquisition of certain assets of Sanofi, a French société anonyme (Sanofi), including all of the outstanding equity interests of Genzyme Biosurgery ApS (Genzyme Denmark), a wholly-owned subsidiary of Sanofi, and over 250 patents and patent applications of Sanofi and certain of its subsidiaries and assumed certain liabilities for purposes of acquiring the portion of the cell therapy and regenerative medicine business (the CTRM Business), which researches, develops, manufactures, markets and sells Carticel®, MACI™ and Epicel® (the CTRM Transaction). The CTRM Business researches, develops, manufactures, markets and sells the Carticel, MACI and Epicel products. As a result, the Company exited the development stage, and is now a fully integrated, commercial-stage biopharmaceutical company dedicated to the identification, development and commercialization of innovative therapies that enable the body to repair and regenerate damaged tissues and organs to restore normal structure and function. Vericel has marketed products as well as developmental stage product candidates and the Company’s goal is to become the leader in cell therapy and regenerative medicine by developing, manufacturing and marketing best-in-class therapies for patients with significant unmet medical needs. The Company operates its business primarily in the U.S. in one reportable segment — the research, product development, manufacture and distribution of patient-specific, expanded cellular therapies for use in the treatment of specific diseases. Successful future operations are subject to several technical hurdles and risk factors, including satisfactory product development, timely initiation and completion of clinical trials, regulatory approval and market acceptance of the Company’s products, and the successful integration and profitability of the CTRM Business.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2014

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements include the accounts of Vericel and its wholly-owned subsidiaries, Aastrom Biosciences GmbH, located in Berlin, Germany, Marrow Donation, LLC, located in San Diego, California, and Astrom BIOSCIENCES DK ApS, in Kastrup, Demark (collectively, the Company). All inter-company transactions and accounts have been eliminated in consolidation. Aastrom Biosciences GmbH ceased operations in 2014.

Use of Estimates

The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reported period. Actual results could differ from those estimates.

Inventory

Inventories are measured at the lower of cost or market value. Cost is calculated based upon standard-cost which approximates costs determined on the first-in, first-out method. Utilization reserves are established for estimated obsolescence or un-marketable inventory in an amount equal to the cost of inventory.

Accounts Receivable

Accounts receivable is initially recorded at the contractual amount owed by the customer. Allowances for doubtful accounts are established when the facts and circumstances indicate that a receivable may not be collectible.

Property, Plant and Equipment

Property, plant and equipment are initially measured and recognized at acquisition cost, including any directly attributable cost of preparing the asset for its intended use or, in the case of assets acquired in a business combination, at fair value as at the date of the combination. After initial measurement, property, plant and equipment are carried at cost less accumulated depreciation and impairment. Repair and maintenance costs of property, plant and equipment are expensed as incurred.

The depreciable value of property, plant and equipment, net of any residual value, is depreciated on a straight line basis over the useful life of the asset. The useful life of an asset is usually equivalent to its economic life. The useful lives of property, plant and equipment are as follows:

Equipment and computers: 3 to 5 years

Furniture and fixtures: 5 years

Building improvements and leasehold improvements: Shorter of the remaining life of the lease or 7 years

The costs of assets retired or otherwise disposed of and the accumulated depreciation thereon are removed from the accounts, with any gain or loss realized upon sale or disposal credited or charged to operations.

Intangible Assets and Other Long Lived Assets

Intangible assets are initially measured at acquisition cost, including any directly attributable costs of preparing the asset for its intended use or, in the case of assets acquired in a business combination at fair value as at the date of the combination. Identifiable intangible assets related to commercial rights are amortized on a straight line basis over their expected useful lives. Amortization of intangible assets is recognized in these financial statements under Costs of product sales.

Intangible assets and long-lived assets are assessed for potential impairment when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. An impairment loss would be recognized when an asset’s fair value, determined based on undiscounted cash flows expected to be generated by the asset, is less than its carrying amount. The impairment loss would be measured as the amount by which the asset’s carrying value exceeds its fair value and recognized in these financial statements. Intangible assets are carried at cost less accumulated amortization and impairment.

Foreign Currency Translation

Assets and liabilities of Genzyme Denmark are translated from Danish Krone into U.S. dollars using the applicable exchange rates in effect at the period end. Expenses of the operations in Denmark are translated from the applicable currencies into U.S. dollars using average exchange rates for the reported period.

Revenue Recognition

Total revenues are comprised of product sales of Carticel, Epicel, MACI, bone marrow and surgical kits. Revenue is recognized when persuasive evidence of an arrangement exists, the goods are shipped or delivered, depending on shipping terms, title and risk of loss pass to the customer and collectability is reasonably assured. Shipping and handling costs are included as a component of revenue.

Revenue is recorded net of a provision for rebates and cash discounts. These rebates and cash discounts are established by the Company at the time of sale, based on historical experience adjusted to reflect known changes in the factors that impact such reserves. For instance, distributors are entitled to chargeback incentives for services that are provided for based on the selling price to the end customer, under specific contractual arrangements. Cash discounts may also be granted for prompt payment.

Research and Development Expense

Research and development activities represent a significant part of the Company’s business. These expenditures relate to the development of new products, improvement of existing products, technical support of products and compliance with governmental regulations for the protection of consumers and patients. Research and development expenses are expensed as incurred.

Diversity of Credit Risk

The Company has established guidelines relative to diversification in an effort to limit risk. These guidelines are periodically reviewed and modified to take advantage of trends in yields and interest rates.

Stock-Based Compensation

The Company’s accounting for stock-based compensation requires it to determine the fair value of common stock issued in the form of stock option awards. The Company uses the value of its common stock at the date of the grant in the calculation of the fair value of its share-based awards. The fair value of stock options held by the employees is determined using a Black-Scholes option valuation method, which is a valuation technique that is acceptable for share-based payment accounting. Key assumptions in determining fair value include volatility, risk-free interest rate, dividend yield and expected term. The assumptions used in calculating the fair value of stock options represent the Company’s best estimates, however; these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the stock-based compensation expense could be materially different in the future. In addition, the Company is required to estimate the expected forfeiture rate and only recognize expense for those stock options expected to vest over the service period. The estimated forfeiture rate considers the historical experience of the Company’s stock-based awards. If the actual forfeiture rate is different from the estimate, expense is adjusted accordingly.

Income Taxes

Deferred tax assets are recognized for deductible temporary differences and tax credit carryforwards and deferred tax liabilities are recognized for taxable temporary differences. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized.

Net Loss Per Share Attributable to Common Shareholders

Basic earnings (loss) per share is calculated using the two-class method, which is an earnings allocation formula that determines earnings (loss) per share for the holders of the Company’s common shares and holders of the Series B preferred stock. The Series B preferred stock shares contain participation rights in undistributed earnings, but do not share in the losses of the Company. The accumulated but undeclared dividends on the Series B preferred stock of $6.0 million are treated as a reduction of earnings attributable to common shareholders.

Financial Instruments

The Company’s financial instruments include receivables for which the current carrying amounts approximate market value based upon their short-term nature.

Warrants

Warrants that could be cash settled or have anti-dilution price protection provisions are recorded as liabilities at their estimated fair value at the date of issuance, with subsequent changes in estimated fair value recorded in other income (expense) in our statement of operations in each subsequent period. In general, warrants are measured using the Black-Scholes valuation model. The methodology is based, in part, upon inputs for which there is little or no observable market data, requiring the Company to develop its own assumptions. The assumptions used in calculating the estimated fair value of the warrants represent our best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the warrant liability and the change in estimated fair value could be materially different.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

+ References+ Details

Recent Accounting Pronouncements	12 Months Ended
Recent Accounting Pronouncements	Dec. 31, 2014
Recent Accounting Pronouncements
Recent Accounting Pronouncements	3. Recent Accounting Pronouncements Revenue Recognition In May 2014, the Financial Accounting Standards Board (FASB) issued authoritative guidance requiring entities to apply a new model for recognizing revenue from contracts with customers. The guidance will supersede the current revenue recognition guidance and require entities to evaluate their revenue recognition arrangements using a five step model to determine when a customer obtains control of a transferred good or service. The guidance is effective for annual reporting periods beginning after December 15, 2016 and may be adopted using a full or modified retrospective application. The Company is currently in the process of evaluating its revenue arrangements under the issued guidance and has not yet determined the impact to its consolidated financial statements. Going Concern Assessment The FASB has issued authoritative guidance for management on how to assess whether substantial doubt exists regarding an entity’s ability to continue as a going concern and guidance on how to prepare related footnote disclosures. The guidance will require management to evaluate whether there are conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern for one year from the date the financial statements are issued. The guidance is effective for annual reporting periods beginning after December 15, 2016. As of December 31, 2014, the Company does not expect the guidance to impact future disclosures.

- Definition

The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 01

-Paragraph b

-Subparagraph 6

-Article 10

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 270

-SubTopic 10

-Section 45

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6372559&loc=d3e765-108305

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 270

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6372559&loc=d3e725-108305

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 250

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22499-107794

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 250

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22580-107794

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Direct Effects of a Change in Accounting Principle

-URI http://asc.fasb.org/extlink&oid=6510796

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Indirect Effects of a Change in Accounting Principle

-URI http://asc.fasb.org/extlink&oid=6515603

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accounting Change

-URI http://asc.fasb.org/extlink&oid=6503790

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Change in Accounting Principle

-URI http://asc.fasb.org/extlink&oid=6507316

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 270

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.10-01.(b)(6))

-URI http://asc.fasb.org/extlink&oid=27015980&loc=d3e46468-122699

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Retrospective Application

-URI http://asc.fasb.org/extlink&oid=6523989

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 250

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22583-107794

+ Details

Acquisitions

12 Months Ended

Dec. 31, 2014

Acquisitions

Acquisitions

4. Acquisitions

CTRM Business acquisition

On May 30, 2014, Vericel completed its acquisition of certain assets of Sanofi, including all of the outstanding equity interests of Genzyme Denmark, a wholly-owned subsidiary of Sanofi, and over 250 patents and patent applications and assumed certain liabilities for purposes of acquiring portions of the CTRM Business. Vericel Corporation is a leader in developing patient-specific expanded cellular therapies for use in the treatment of patients with severe diseases and conditions. The CTRM Business, also a leading developer of patient-specific expanded cellular therapies, expands the Company’s portfolio of cellular therapies to include products which treat severe burns and as well as cartilage defects. The CTRM Business is a commercial business, with manufacturing, marketing and sales capabilities. Pursuant to the terms of the asset purchase agreement, the Company paid a total purchase price of $6.5 million, including $4.0 million in cash and a $2.5 million promissory note which was repaid on July 30, 2014.

The total purchase price consideration is as follows:

Acquisition consideration (In thousands):	Fair Value
Cash payment	$	4,000
Promissory note	2,500
Total acquisition consideration	$	6,500

The Company recognized tangible and intangible assets and liabilities acquired based upon their respective estimated fair values as of the acquisition date. The table below shows the fair values assigned to the assets acquired and liabilities assumed. Based on this analysis, the transaction resulted in a bargain purchase gain.

The final purchase price allocation is as follows:

Purchase price allocation (In thousands):	Fair Value
Cash	$	5,050
Accounts receivable	53
Inventory	2,039
Other current assets	192
Accounts payable and accrued expenses	(939		)
Asset retirement obligation	(1,600		)
Property and equipment	1,818
Intangible assets	3,360
Bargain purchase gain	(3,473		)
Total consideration	$	6,500

As part of the acquisition, the Company received $5.0 million in cash from Sanofi in order to fund a restructuring of the Denmark operations and close the facility. As of December 31, 2014, the Company has recorded restructuring charges of $3.0 million. See Note 5 “Restructuring” below for additional information.

The intangible assets acquired represent commercial use rights for certain products acquired in the transaction. This fair value of $3.4 million was determined using the income approach based on projected cash flows attributed to the commercial rights. The calculated value of the commercial rights intangible assets are amortized using the straight line method over an estimated useful life of twelve years.

Revenue and net income included in the condensed consolidated financial statements include seven months of operations related to the CTRM Business since the May 30, 2014 acquisition and are $28.4 million and $0.4 million, respectively. The net income related to the CTRM Business includes the restructuring costs of $3.0 million described in Note 5 as well as $0.4 million of other expenses from the Danish subsidiary that the Company is in the process of shutting down.

The following pro forma condensed combined information for the year ended December 31, 2014, and 2013, respectively are presented as if the acquisition of the CTRM Business had occurred on January 1, 2013.

In management’s opinion, all adjustments necessary to reflect the significant effects of this transaction have been made. These statements are based on assumptions and estimates considered appropriate by management; however, they are not necessarily, and should not be assumed to be, an indication of Vericel’s financial position or results of operations that would have been achieved had the acquisitions been completed as of the dates indicated or that may be achieved in the future.

	Year Ended December 31,
(in thousands)	2014			2013
Pro forma revenue	$	44,794		$	43,863
Pro forma net loss	(26,106		)	(49,124		)
Pro forma net loss per share — basic and diluted	$	(2.77	)	$	(18.06	)

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6996-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7000-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4922-128472

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4926-128472

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4934-128472

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1383-128463

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1486-128463

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1497-128463

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1490-128463

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

Reference 14: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1500-128463

Reference 15: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1524-128463

+ Details

Restructuring	12 Months Ended
Restructuring	Dec. 31, 2014
Restructuring
Restructuring	5. Restructuring Acquisition Restructuring In June 2014, the Company announced a strategic plan to maximize the profitability and growth potential of the CTRM Business (the Plan). Under the Plan, the Company discontinued manufacturing MACI in Denmark, temporarily suspended sales of MACI in Europe, and significantly reduced research and development expenses associated with MACI. Furthermore, the Company eliminated approximately 80 full time employee positions, which represented approximately 30% of the Company’s current total workforce. Employees terminated as part the Plan were provided with severance payments and outplacement assistance. As a result of the Plan, the Company recorded a restructuring charge of $3.0 million for the year ended December 31, 2014, related to the operations in the United States and Denmark, primarily representing cash payments for severance and other personnel-related expenses. Of the total restructuring charge, $2.5 million was recorded in cost of product sales, and $0.5 million was recorded in selling, general and administrative expenses. There was no restructuring reserve as of December 31, 2014 as a result of cash payments made for severance and other personnel-related expenses. In addition to restructuring charges recorded thus far, the Company may incur additional lease and other contract termination costs associated with current contracts associated with the Danish operations. R&D Restructuring In March, 2013, the Company announced a strategic change in its research and development programs to focus on the clinical development of ixmyelocel-T for the treatment of advanced heart failure due to ischemic dilated cardiomyopathy (DCM). The Company previously received a U.S. orphan drug designation for the use of ixmyelocel-T in the treatment of DCM. As a result of the strategic change, the Company stopped enrollment of the Phase 3 REVIVE clinical trial in patients with critical limb ischemia (CLI). In addition, the Company executed a corporate restructuring that reduced staff and operating expenses. Employees directly affected by the restructuring plan were provided with severance payments and outplacement assistance. As a result of the ceasing of enrollment in the Phase 3 REVIVE clinical trial, the Company recorded a one-time restructuring charge of $0.4 million in the first quarter of 2013 in research and development expenses. The restructuring accrual for the strategic changes decreased to less than $0.1 million as of December 31, 2013 as a result of cash payments made for severance and other personnel-related expenses. There was no restructuring reserve related to the strategic change as of December 31, 2014.

- Definition

The entire disclosure for restructuring and related activities. Description of restructuring activities such as exit and disposal activities, include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled.

+ References+ Details

Selected Balance Sheet Components

12 Months Ended

Dec. 31, 2014

Selected Balance Sheet Components

Selected Balance Sheet Components

6. Selected Balance Sheet Components

Inventory as of December 31, 2014:

(In thousands)	2014
Raw materials	$	1,078
Work-in-process	458
Finished goods	384
Inventory	$	1,920

Property and Equipment, net as of December 31, 2014 and 2013:

(In thousands)	2014			2013
Machinery and equipment	$	3,135		$	2,547
Furniture, fixtures and office equipment	777			761
Computer equipment and software	667			500
Leasehold improvements	1,691			1,018
Construction in process	1,019			—
	7,289			4,826
Less accumulated depreciation	(4,397		)	(4,087		)
	$	2,892		$	739

Depreciation expense for the years ended December 31, 2014, 2013 and 2012 were $0.8 million, $0.5 million and $0.6 million, respectively.

Intangible assets, net as of December 31, 2014:

(In thousands)	2014
Commercial rights	$	3,360
Less accumulated amortization	(163		)
	$	3,197

Amortization expense was $0.2 million for the year ended December 31, 2014. There was no amortization expense in 2013. The increase in intangible assets from December 31, 2013 to December 31, 2014 is due to the acquisition of the CTRM Business.

Estimated future amortization expense is as follows:

Calendar Years Ending December 31, (In thousands)
2015	$	280
2016	280
2017	280
2018	280
2019	280
Thereafter	1,797
Total	$	3,197

Accrued Expenses as of December 31, 2014 and 2013:

(In thousands)	2014		2013
Bonus	$	2,044	$	387
Employee related accruals	1,281		233
Accrued expenses	605		—
Asset retirement obligation	348		—
Other	436		—
	$	4,714	$	620

The Company acquired an asset retirement obligation of $1.6 million related to the obligation to restore the Denmark facility to its original state which was reduced to $0.3 million during the fourth quarter of 2014 due to a change in estimate.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2014

Stock-Based Compensation

Stock-Based Compensation

7.Stock-Based Compensation

Stock Option and Equity Incentive Plans

The Company has historically had various stock incentive plans and agreements that provide for the issuance of nonqualified and incentive stock options as well as other equity awards. Such awards may be granted by the Company’s Board of Directors to certain of the Company’s employees, directors and consultants. Options granted under these plans expire no later than ten years from the date of grant, and other than those granted to non-employee directors, generally become exercisable over a four-year period, under a graded-vesting methodology, following the date of grant. The Company generally issues new shares upon the exercise of stock options.

The 2009 Omnibus Incentive Plan (2009 Plan) provides incentives through the grant of stock options, stock appreciation rights, restricted stock awards and restricted stock units. The exercise price of stock options granted under the 2009 Plan shall not be less than the fair market value of the Company’s common stock on the date of grant. The 2009 Plan replaced the 1992 Stock Option Plan, the 2001 Stock Option Plan and the Amended and Restated 2004 Equity Incentive Plan (Prior Plans), and no new awards will be granted under the Prior Plans. However, the expiration or forfeiture of options previously granted under the Prior Plans will increase the awards available for issuance under the 2009 Plan.

As of December 31, 2014, there were 4,011,608 shares available for future grant under the 2009 Plan.

Service-Based Stock Options

During the period ended December 31, 2014, the Company granted 242,025 service-based options to purchase common stock. The exercise price of the options is the fair market value per share of common stock on the grant date, generally vest over four years (other than 12,000 non-employee options which generally vest over one year) and have a term of ten years. The weighted average grant-date fair value of service-based options granted during the years ended December 31, 2014, 2013 and 2012 was $2.85, $14.07 and $24.00, respectively.

The net compensation costs recorded for the service-based stock options related to employees and directors (including the impact of the forfeitures) for the years ended December 31, 2014, 2013 and 2012 were $0.8 million, $0.9 million and $3.6 million, respectively.

The fair value of each service-based stock option grant for the reported periods is estimated on the date of the grant using the Black-Scholes option-pricing model using the weighted average assumptions noted in the following table.

	Year Ended December 31,
Service-Based Stock Options	2014	2013	2012
Expected dividend rate	0%	0%	0%
Expected stock price volatility	82.4% - 88.2%	74.0% – 87.9%	73.9% – 79.1%
Risk-free interest rate	1.66% - 2.2%	0.1% – 2.1%	0.9% – 1.5%
Expected life (years)	5.5 – 6.3	5.0 – 6.3	5.5 – 6.3

The following table summarizes the activity for service-based stock options for the indicated periods:

Service-Based Stock Options	Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at December 31, 2011	403,984		$	47.60	8.4	$	674,000
Granted	273,372		$	44.20
Exercised	(7,208	)	$	29.60		$	52,000
Cancelled	(52,885	)	$	40.60
Forfeited or expired	(117,889	)	$	43.60
Outstanding at December 31, 2012	499,374		$	47.60	7.5	$	—
Granted	75,751		$	21.32
Exercised	—		$	—		$	—
Expired	(164,189	)	$	51.76
Forfeited	(113,076	)	$	45.38
Outstanding at December 31, 2013	297,860		$	39.53	7.9	$	—
Granted	242,025		$	3.91
Exercised	—		$	—		$	—
Expired	(32,012	)	$	42.63
Forfeited	(30,347	)	$	32.13
Outstanding at December 31, 2014	477,530		$	21.74	8.0	$	—
Exercisable at December 31, 2014	209,375		$	36.43	6.9	$	—

As of December 31, 2014, there was approximately $0.8 million, of total unrecognized compensation cost related to non-vested service-based stock options granted under the 2009 Plan and the Prior Plans. That cost is expected to be recognized over a weighted-average period of 2.82 years.

The total fair value of stock options vested for the years ended December 31, 2014, 2013 and 2012 was $1.5 million, $2.3 million $3.0 million, respectively.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References+ Details

Shareholders' Equity	12 Months Ended
Shareholders' Equity	Dec. 31, 2014
Shareholders' Equity
Shareholders' Equity	8.Shareholders’ Equity 2013 Stock and Warrant Sale On August 16, 2013, the Company completed the sale of 1.5 million shares of common stock and warrants to purchase up to an aggregate of 1.5 million shares of common stock (including 50,000 shares of common stock and warrants sold to the underwriter pursuant to the exercise of its over-allotment option). Each share of common stock and its associated warrant was sold at a public offering price of $6.00 per share. The Company received $8.2 million in net proceeds from the sale of the shares of common stock and warrants (including the partial exercise of the over-allotment option), after underwriting discounts, commissions and other offering expenses. The total fair market value of the warrants at the date of issuance was $5.9 million. The sales proceeds were first allocated to the warrants based on the total fair market value and the residual amount of the sales proceeds were allocated to common stock. 2014 Warrant Exercises On July 9, 2014, the Company entered into a Warrant Exercise Agreement with one holder of warrants issued by the Company on August 16, 2013 (the 2013 Warrants) to purchase an aggregate of 362,500 shares of the Company’s common stock, no par value. Pursuant to the Warrant Exercise Agreement, the holder agreed to exercise the 2013 Warrants at the existing exercise price of $4.80. The net proceeds to the Company in connection with the exercise of the 2013 Warrants, after deducting a warrant inducement payment and expenses, were approximately $1.5 million. 2014 Stock Purchase Agreement On January 21, 2014, the Company entered into a purchase agreement (Purchase Agreement), together with a registration rights agreement, for the sale of up to $15.0 million of shares of its common stock to Lincoln Park, subject to certain limitations, from time to time over a 30-month period, which began on April 3, 2014 and ends on October 3, 2016. The Company may direct Lincoln Park, at its sole discretion, to purchase up to 50,000 shares of common stock in regular purchases, increasing to amounts of up to 100,000 shares depending upon the closing sale price of the common stock. In addition, the Company may direct Lincoln Park to purchase additional amounts as accelerated purchases if on the date of a regular purchase the closing sale price of the common stock equals or exceeds $3.00 per share. The purchase price of shares of common stock related to the future funding will be based on the prevailing market prices of such shares at the time of sales (or over a period of up to 10 business days leading up to such time), but in no event will shares be sold to Lincoln Park on a day the common stock closing price is less than the floor price of $2.50, subject to adjustment. The Company controls the timing and amount of any sales of common stock to Lincoln Park. The Company’s sales of shares of common stock to Lincoln Park under the Purchase Agreement are limited to no more than the number of shares that would result in the beneficial ownership by Lincoln Park and its affiliates, at any single point in time, of more than 9.99% of the then outstanding shares of the common stock. For the year ended December 31, 2014, the Company issued 935,499 shares of common stock to Lincoln Park and raised gross proceeds of $3.7 million (with the ability to sell up to an additional $11.3 million more in common stock). At-the-Market Sales Agreement During the years ended December 31, 2014 and 2013, the Company raised net proceeds of $7.1 million and $4.8 million utilizing the At-the-Market Sales Agreement (ATM) with MLV & Co. LLC (formerly McNicoll, Lewis & Vlak) (MLV). The Company originally entered into the ATM with MLV in June 2011 in which the Company may sell shares of its common stock through MLV, as sales agent, in registered transactions from its shelf registration statement filed in July 2011, for aggregate proceeds of up to $20.3 million. Shares of common stock sold under the ATM are to be sold at market prices. The Company will pay up to 3% of the gross proceeds to MLV as a commission. At December 31, 2014 there was approximately $7.8 million of net capacity remaining on the ATM. 2014 Public Equity Offering On September 17, 2014, the Company closed on a public equity offering whereby it sold 15,784,313 shares of common stock at an offering price of $2.55 per share (the 2014 offering). The proceeds of $37.5 million, net of $2.4 million of underwriters’ discount and $0.3 million of issuance costs consisting primarily of legal and accounting fees, were recorded as a common stock issuance. Dividends No cash dividends have been declared or paid by the Company since its inception.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29-31)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 4.E)

-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 4

-Subparagraph (SAB TOPIC 4.C)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section C

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section E

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(d),(e))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Preferred Stock

-URI http://asc.fasb.org/extlink&oid=6521494

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 14: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 15: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 17: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 18: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph d

-Article 4

Reference 19: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

+ Details

Net Loss Per Common Share

12 Months Ended

Dec. 31, 2014

Net Loss Per Common Share

Net Loss Per Common Share

9. Net Loss Per Common Share

The following reflects the net loss attributable to common shareholders and share data used in the basic and diluted earnings per share computations using the two class method:

	Year Ended December 31,
(Amounts in thousands, except per share amounts)	2014			2013			2012
Numerator:
Net loss	$	(19,920	)	$	(15,622	)	$	(29,474	)
Less: earnings attributable to convertible preferred stock	6,005			5,352			3,993
Numerator of basic and diluted EPS	$	(25,925	)	$	(20,974	)	$	(33,467	)

Denominator:
Denominator for basic and diluted EPS: weighted- average common shares outstanding	11,642			3,016			2,060
Net loss per share attributable to common shareholders (basic and diluted)	$	(2.23	)	$	(6.95	)	$	(16.25	)

Common equivalent shares are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive. The aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from the computations of diluted net loss per common share for the years ended December 31, 2014, 2013 and 2012 was 2.3 million, 2.4 million and 1.4 million, respectively.

- Definition

The entire disclosure for earnings per share.

+ References+ Details

Stock Purchase Warrants

12 Months Ended

Dec. 31, 2014

Stock Purchase Warrants

Stock Purchase Warrants

10. Stock Purchase Warrants

The Company has historically issued warrants to purchase shares of the Company’s common stock in connection with certain common stock offerings. The following warrants were outstanding during the years ended December 31, 2014, 2013 and 2012, and include provisions that could require cash settlement of the warrants or have anti-dilution price protection provisions requiring each to be recorded as liabilities of the Company at the estimated fair value at the date of issuance, with changes in estimated fair value recorded as non-cash income or expense in the Company’s statement of operations in each subsequent period:

	January 2010 Class A Warrants		December 2010 Warrants		August 2013 Warrants
Exercise price	$	7.86	$	2.55	$	4.80
Expiration date	July 21, 2015		December 15, 2015		August 16, 2018
Total shares issuable on exercise	226,299		15,405		724,950

The fair values of the warrants are measured using the Black-Scholes valuation model. The methodology is based, in part, upon inputs for which there is little market data, requiring the Company to develop its own assumptions. The assumptions used in calculating the estimated fair value of the warrants represent the Company’s best estimates, however; these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the warrant liabilities and the change in estimated fair value of the warrants could be materially different.

Inherent in the Black-Scholes valuation model are assumptions related to expected stock-price volatility, expected life, risk-free interest rate and dividend yield. The Company estimates the volatility of its common stock based on historical volatility that matches the expected remaining life of the warrants. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield curve on the grant date for a maturity similar to the expected remaining life of the warrants. The expected life of the warrants is assumed to be equivalent to their remaining contractual term. The dividend rate is based on the historical rate, which the Company anticipates to remain at zero.

The assumptions used by the Company are summarized in the following tables:

January 2010 Class A Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	45.1		%	84.6		%
Risk-free interest rate	0.1		%	0.3		%
Expected life (years)	0.55			1.50

December 2010 Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	99.7		%	80.4		%
Risk-free interest rate	0.2		%	0.4		%
Expected life (years)	0.96			1.96

August 2013 Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	83.2		%	77.5		%
Risk-free interest rate	1.2		%	1.6		%
Expected life (years)	3.63			4.63

Fair Value Measurements

12 Months Ended

Dec. 31, 2014

Fair Value Measurements

Fair Value Measurements

11. Fair Value Measurements

The Company’s fair value measurements are classified and disclosed in one of the following three categories:

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability;

Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

The following table summarizes the valuation of the Company’s investments and financial instruments that are measured at fair value on a recurring basis:

	December 31, 2014								December 31, 2013
	Fair value measurement category								Fair value measurement category
(In thousands)	Total		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3
Liabilities:
Warrant liabilities	$	1,081	$	—	$	1,061	$	20	$	2,019	$	—	$	1,934	$	85

The fair values of the warrants are measured using the Black-Scholes valuation model. See Note 10 for further discussion of the significant observable inputs use to measure the warrant liabilities.

The following table summarizes the change in the estimated fair value of the Company’s warrant liabilities:

Warrant Liabilities (In thousands)
Balance at December 31, 2012	$	1,995
Warrant issuance	5,874
Warrant exercises	(513		)
Decrease in fair value	(5,337		)
Balance at December 31, 2013	2,019
Warrant issuance	—
Warrant exercises	(965		)
Increase in fair value	27
Balance at December 31, 2014	$	1,081

A reconciliation of beginning and ending balances for the Company’s fair value measurements using Level 3 inputs is as follows:

Warrants:

	Year Ended
(In thousands)	December 31, 2014			December 31, 2013
Beginning balance	$	85		$	1,995
Decrease in fair value	(65		)	(1,910		)
Ending balance	$	20		$	85

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References+ Details

Income Taxes

12 Months Ended

Dec. 31, 2014

Income Taxes

Income Taxes

12. Income Taxes

Income (loss) before income taxes for U.S and non-U.S operations was as follows:

	Year Ended December 31,
	2014			2013			2012
U.S. loss	$	(18,078	)	$	(15,622	)	$	(29,474	)
Non U.S. loss	(1,842		)	—			—
	$	(19,920	)	$	(15,622	)	$	(29,474	)

A reconciliation of income taxes computed using the federal statutory rate to the taxes reported in the consolidated statements of operations is as follows:

	Year Ended December 31,
(In thousands)	2014			2013			2012
Loss before income taxes	$	19,920		$	15,622		$	29,474
Federal statutory rate	34		%	34		%	34		%
Taxes computed at federal statutory rate	(6,773		)	(5,311		)	(10,021		)
State taxes (net of federal benefit)	(463		)	—			—
Warrants	(10		)	(1,815		)	(1,445		)
Nondeductible stock compensation	48			81			872
Michigan NOL benefit	—			(791		)	(1,229		)
Net operating loss expirations	655			612			612
Write-off of Section 382 limited NOL’s	67,781			—			—
Write-off of Section 383 limited R&D credits	1,600			—			—
Other	352			(27		)	300
Change in valuation allowance	(63,190		)	7,251			10,911
Reported income taxes	$	—		$	—		$	—

Deferred tax assets consist of the following:

	Year Ended December 31,
(In thousands)	2014			2013
Net operating loss carryforwards	$	7,092		$	70,738
Research and development credit carryforwards	—			1,600
Employee benefits and stock compensation	1,897			1,655
Research and development costs	2,184			—
Fixed assets	254			—
Intangible assets	(510		)	—
Asset Retirement obligation	127			—
Other, net	301			524
Total deferred tax assets	11,345			74,517
Valuation allowance	(11,345		)	(74,517		)
Net deferred tax assets	$	—		$	—

On September 17, 2014, the Company underwent a change in control as defined by Section 382 of the Internal Revenue Code. A change in control is generally defined as a cumulative change of 50% or more in the ownership positions of certain stockholders during a rolling three year period. This change in control resulted in substantial limitations being placed on certain tax attributes including net operating losses and tax credit carryforwards. The limitations are computed based upon several variable factors including the value of the Company on the date of the change in control. The projected annual limitation on the use of the net operating losses that existed prior to September 17, 2014 is $0.8 million. As a result, a significant portion of the net operating losses and tax credit carryforwards will expire prior to their utilization, regardless of the level of future profitability. Accordingly, the Company reduced our net operating losses and tax credit carryforwards (with a corresponding adjustment to our valuation allowance) to reflect the amount available to offset future profits.

As of December 31, 2014, the Company’s U.S. federal, and state tax net operating loss carryforwards available to offset future profits, after considering the aforementioned annual Section 382 limit, are $19.3 million and $7.8 million, respectively. These net operating loss carryforwards will expire between 2015 and 2034.

In accordance with the accounting guidance for income taxes, the Company estimated whether recoverability of its deferred tax assets is “more likely than not,” based on forecasts of taxable income in the related tax jurisdictions. In this estimate, the Company uses historical results, projected future operating results based upon approved business plans, eligible carry forward periods, tax planning opportunities and other relevant considerations. Based on these factors, including historical losses incurred by the Company, a full valuation allowance for the deferred tax assets, including the deferred tax assets for the aforementioned net operating losses and credits, has been provided since they are not more likely than not to be realized. If the Company achieves profitability, these deferred tax assets may be available to offset future income taxes. The decrease in the valuation allowance was $63.2 million for the year ended December 31, 2014 and a $7.3 million increase for the year ended December 31, 2013.

The Company assesses uncertain tax positions in accordance with the guidance for accounting for uncertain tax positions. This pronouncement prescribes a recognition threshold and measurement methodology for recording within the financial statements uncertain tax positions taken, or expected to be taken, in the Company’s income tax returns. To the extent the uncertain tax positions do not meet the “more likely than not” threshold, the Company has derecognized such positions. To the extent the uncertain tax positions meet the “more likely than not” threshold, the Company has measured and recorded the highest probable benefit, and have established appropriate reserves for benefits that exceed the amount likely to be sustained upon examination.

A reconciliation of the beginning and ending amounts of uncertain tax provision is as follows:

	Unrecognized Income Tax
(In thousands)	Benefits
Balance at December 31, 2012	$	2,100
Decrease in prior year tax positions	(1,200		)
Balance at December 31, 2013	900
Decrease in prior year tax positions	(900		)
Balance at December 31, 2014	$	—

It is not anticipated that the unrecognized tax benefits will significantly increase or decrease within the next twelve months.

The Company files U.S. federal, Michigan and California income tax returns. Due to the Company’s net operating loss carryforwards, Federal income tax returns from incorporation are still subject to examination. Michigan tax returns for the year ended December 31, 2012 and forward are subject to examination. California tax returns for the year ended December 31, 2012 and forward are subject to examination.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References+ Details

Concentration of Credit	12 Months Ended
Concentration of Credit	Dec. 31, 2014
Concentration of Credit
Concentration of Credit	13. Concentration of Credit Revenue from one customer, a distributor in the U.S., represented approximately 76% of total revenue during the year ended December 31, 2014. Excluding that distributor, the largest customer represented approximately 10% of revenue for the year ended December 31, 2014 and no other customer accounted for more than 10% of revenue reported. Revenue primarily reflects sales related to the acquisition of the CTRM Business from Sanofi since May 30, 2014.

- Definition

The entire disclosure for any concentrations existing at the date of the financial statements that make an entity vulnerable to a reasonably possible, near-term, severe impact. This disclosure informs financial statement users about the general nature of the risk associated with the concentration, and may indicate the percentage of concentration risk as of the balance sheet date.

+ References+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies

Commitments and Contingencies

14. Commitments and Contingencies

Licenses, Royalties and Collaborative Agreements

University of Michigan — In 1989, the Company entered into a research agreement with the University of Michigan (the University) and in 1992, as provided for under the research agreement, the Company also entered into a license agreement for the technology developed under the research agreement. The license agreement, as amended, provides for a royalty to be paid to the University equal to 2% of net sales of products containing the licensed technology sold by the Company. Such royalties have been nominal since Inception. This license agreement expired in 2014.

Corning Incorporated — In December 2002, the Company entered into an agreement with Corning Incorporated (Corning) that granted Corning an exclusive sublicense relating to the Company’s cell transfection technology. Under the terms of the agreement, the Company retains exclusive rights to the applications of the technologies involving cells for therapeutic applications. In addition, the agreement provides for future royalty payments on net sales of licensed products sold under the sublicense amounting to 5% of such sales up to $50,000,000. However, the Company does not expect to receive material revenue from this source for several years, if ever.

RealBio Technologies — In May 2009, the Company entered into an agreement with RealBio Technologies, Inc. (RealBio) that granted RealBio an exclusive license to utilize our technology outside of the Company’s core area of focus - human regenerative medicine. In return for this license, the Company received a minority equity interest in RealBio, which was not material as of December 31, 20142013.

Manufacture, Supply and Other Agreements — The Company has entered into various agreements relating to the manufacture of its products and the supply of certain components. If the manufacturing or supply agreements expire or are otherwise terminated, the Company may not be able to identify and obtain ancillary materials that are necessary to develop its product and such expiration and termination could have a material effect on the Company’s business.

Operating Leases

The Company renewed their operating lease in Ann Arbor, Michigan to extend the term of the lease for an additional five years, which began on May 1, 2013. The Company has a right to terminate on the third anniversary of the renewal, and has two five-year market value renewal options. In March 2015, the Company subleased a portion of the property in Ann Arbor which is reflected in the future minimum payments below. The Company also leases property in Cambridge, Massachusetts and Kastrup, Denmark which expire in February 2017. The Company has a right to extend the Cambridge operating lease for two three-year market value renewal options. In addition to the property leases, the Company also leases various vehicles and computer equipment.

As of December 31, 2014, future minimum payments related to Vericel’s operating and capital leases are as follows:

			Payments Due by Period
Contractual Obligations	Total		2015		2016		2017		2018		More than 5 Years
Operating leases	$	9,809	$	4,215	$	4,023	$	1,323	$	248	$	—
Capital leases	152		43		43		43		23		—
Total	$	9,961	$	4,258	$	4,066	$	1,366	$	271	$	—

Rent expense for the years ended December 31, 2014, 2013 and 2012, was $2.5 million, $1.0 million and $1.1 million, respectively.

- Definition

The entire disclosure for commitments and contingencies.

+ References+ Details

Employee Savings Plan	12 Months Ended
Employee Savings Plan	Dec. 31, 2014
Employee Savings Plan
Employee Savings Plan	15. Employee Savings Plan The Company has a 401(k) savings plan that allows participating employees to contribute a portion of their salary, subject to annual limits and minimum qualifications. The Board may, at its sole discretion, approve Company matching contributions to the plan. The Company made contributions of $0.3 million, $0.1 million and $0.2 million for the years ended December 31, 2014, 2013 and 2012, respectively.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References+ Details

Preferred Stock	12 Months Ended
Preferred Stock	Dec. 31, 2014
Preferred Stock.
Preferred Stock	16. Preferred Stock Shareholder Rights Plan In August 2011, the Board of Directors of the Company adopted a Shareholder Rights Plan, as set forth in the Shareholder Rights Agreement between the Company and the rights agent, the purpose of which is, among other things, to enhance the Board’s ability to protect shareholder interests and to ensure that shareholders receive fair treatment in the event any coercive takeover attempt of the Company is made in the future. The Shareholder Rights Plan could make it more difficult for a third party to acquire, or could discourage a third party from acquiring, the Company or a large block of the Company’s common stock. In March 2012, the Board approved an amendment to the Shareholder Rights Plan to enable Eastern Capital Limited and its affiliates to purchase up to 49.9% of the shares of common stock of the Company without becoming an “acquiring person” and thereby triggering the stockholder rights, with the limitations under the Shareholder Rights Plan remaining in effect for all other stockholders of the Company. In connection with the adoption of the Shareholder Rights Plan, the Board of Directors of the Company declared a dividend distribution of one preferred stock purchase right (Right) for each outstanding share of common stock to stockholders of record as of the close of business on August 15, 2011. In addition, one Right will automatically attach to each share of common stock issued between August 15, 2011 and the distribution date. As a result of the October 2013 reverse stock split, the number of Rights associated with each share of common stock was automatically proportionately adjusted so that (i) twenty rights were then associated with each outstanding share of common stock and (ii) so long as the Rights are attached to the common stock, twenty rights shall be deemed to be delivered for each share of common stock issued or transferred by the Company in the future. The Rights currently are not exercisable and are attached to and trade with the outstanding shares of common stock. Each Right entitles the registered holder of common stock to purchase from the Company a unit consisting of one ten-thousandth of a share (Unit) of Series A Junior Participating Preferred Stock, no par value per share, at a cash exercise prices of $30.00 per Unit. There are currently 45,000 shares authorized and zero issued and outstanding. Under the Shareholder Rights Plan, the Rights become exercisable if a person or group becomes an “acquiring person” by acquiring 15% or more of the outstanding shares of common stock or if a person or group commences a tender offer that would result in that person owning 15% or more of the common stock. If a person or group becomes an “acquiring person,” each holder of a Right (other than the acquiring person and its affiliates, associates and transferees) would be entitled to purchase, at the then-current exercise price, such number of shares of the Company’s preferred stock which are equivalent to shares of common stock having a value of twice the exercise price of the Right. If the Company is acquired in a merger or other business combination transaction after any such event, each holder of a Right would then be entitled to purchase, at the then-current exercise price, shares of the acquiring company’s common stock having a value of twice the exercise price of the Right. The Rights may be redeemed in whole, but not in part, at a price of $0.001 per Right (payable in cash, common stock or other consideration deemed appropriate by the Board of Directors) by the Board of Directors only until the earlier of (i) the time at which any person becomes an “acquiring person” or (ii) the expiration date of the Rights Agreement. Immediately upon the action of the Board of Directors ordering redemption of the Rights, the Right will terminate and thereafter the only right of the holders of Rights will be to receive the redemption price. The Rights will expire at the close of business on August 15, 2021, unless previously redeemed or exchanged by the Company as described above. Series B Convertible Preferred Stock On March 9, 2012, the Company completed the sale of 12,308 shares of Series B-1 Non-Voting Convertible Preferred Stock (Series B-1 preferred stock) at an offering price of $3,250 per share. In addition to the Series B-1 preferred stock, which was issued at the closing, the Company also authorized Series B-2 Voting Convertible preferred Stock (Series B-2 preferred stock). The Series B-1 preferred stock and Series B-2 preferred stock collectively are referred to as the Series B preferred stock. The Series B preferred stock is convertible, at the option of the holder thereof at any time after the five year anniversary of the closing of the offering, into shares of common stock at a conversion price of $3.25 per share of common stock, at a conversion ratio of one share of preferred stock for fifty shares of common stock. At any time after the five year anniversary of issuance, the Company may elect to convert any or all outstanding shares of Series B preferred stock into shares of common stock, subject to certain limitations. Dividends on the Series B preferred stock will be cumulative and compound daily, at a rate of 11.5% per annum, payable upon conversion, liquidation, redemption or other similar events, and payable in cash or Series B-1 preferred stock until the five year anniversary of issuance. As of December 31, 2014, there are 235,077 accumulated but undeclared Series B-1 dividends. Unless prohibited by Michigan law governing distributions to shareholders, the Series B-1 preferred stock shall be redeemable at the option of holder of the Series B-1 preferred stock commencing at any time after the five year anniversary of issuance, liquidation, winding up, dissolution or other similar events, subject to certain terms and limitations. The Series B preferred stock does not, in its entirety, require liability classification and was evaluated for embedded features to determine if those features require bifurcation and separate classification as derivative liabilities. The Series B preferred stock host contract was evaluated for equity or mezzanine classification based upon the nature of the redemption and conversion features. Generally, any feature that could require cash redemption for matters not within the Company’s control, irrespective of probability of the event occurring, requires classification outside of shareholders’ equity. The Series B preferred stock was initially recorded as mezzanine in the Consolidated Balance Sheets and was accreted to its redemption value through charges to accumulated deficit using the effective interest method. On August 12, 2013, the Company amended the Series B preferred stock agreement to remove the cash redemption provision, modify the liquidation preferences for the Series B-2 preferred stock and to increase the redemption price for the Series B-1 preferred stock. The redemption price, prior to the five year anniversary, is now equal to $7,430 multiplied by the number of Series B-1 preferred shares redeemed minus the Company’s closing stock price multiplied by the number of common shares into which the outstanding Series B-2 preferred stock are convertible. The redemption price, after the five year anniversary, is the amount equal to the greater of the Series B offering price plus accrued dividends or the conversion value in common stock. As a result of the amendment to the agreement, the total amount of $38.4 million Series B preferred stock was reclassified from mezzanine into shareholders’ equity.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2014

Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements include the accounts of Vericel and its wholly-owned subsidiaries, Aastrom Biosciences GmbH, located in Berlin, Germany, Marrow Donation, LLC, located in San Diego, California, and Aastrom BIOSCIENCES DK ApS, in Kastrup, Demark (collectively, the Company). All inter-company transactions and accounts have been eliminated in consolidation. Aastrom Biosciences GmbH ceased operations in 2014.

Use of Estimates

Inventory

Accounts Receivable

Property, Plant and Equipment

Equipment and computers: 3 to 5 years

Furniture and fixtures: 5 years

Building improvements and leasehold improvements: Shorter of the remaining life of the lease or 7 years

Intangible Assets and Other Long Lived Assets

Foreign Currency Translation

Revenue Recognition

Research and Development Expense

Diversity of Credit Risk

Stock-Based Compensation

Income Taxes

Net Loss Per Share Attributable to Common Shareholders

Financial Instruments

The Company’s financial instruments include receivables for which the current carrying amounts approximate market value based upon their short-term nature.

Warrants

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2014

Acquisitions

Schedule of total purchase price consideration

Acquisition consideration (In thousands):	Fair Value
Cash payment	$	4,000
Promissory note	2,500
Total acquisition consideration	$	6,500

Schedule of final purchase price allocation

Purchase price allocation (In thousands):	Fair Value
Cash	$	5,050
Accounts receivable	53
Inventory	2,039
Other current assets	192
Accounts payable and accrued expenses	(939		)
Asset retirement obligation	(1,600		)
Property and equipment	1,818
Intangible assets	3,360
Bargain purchase gain	(3,473		)
Total consideration	$	6,500

Schedule of unaudited pro forma condensed combined statements

	Year Ended December 31,
(in thousands)	2014			2013
Pro forma revenue	$	44,794		$	43,863
Pro forma net loss	(26,106		)	(49,124		)
Pro forma net loss per share — basic and diluted	$	(2.77	)	$	(18.06	)

Selected Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2014

Selected Balance Sheet Components

Schedule of inventory

(In thousands)	2014
Raw materials	$	1,078
Work-in-process	458
Finished goods	384
Inventory	$	1,920

Schedule of property and equipment, net

(In thousands)	2014			2013
Machinery and equipment	$	3,135		$	2,547
Furniture, fixtures and office equipment	777			761
Computer equipment and software	667			500
Leasehold improvements	1,691			1,018
Construction in process	1,019			—
	7,289			4,826
Less accumulated depreciation	(4,397		)	(4,087		)
	$	2,892		$	739

Schedule of intangible assets, net

(In thousands)	2014
Commercial rights	$	3,360
Less accumulated amortization	(163		)
	$	3,197

Schedule of estimated future amortization expense

Calendar Years Ending December 31, (In thousands)
2015	$	280
2016	280
2017	280
2018	280
2019	280
Thereafter	1,797
Total	$	3,197

Schedule of accounts payable and accrued expenses

(In thousands)	2014		2013
Bonus	$	2,044	$	387
Employee related accruals	1,281		233
Accrued expenses	605		—
Asset retirement obligation	348		—
Other	436		—
	$	4,714	$	620

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

Stock-Based Compensation

Schedule of weighted average assumptions used to estimate fair value of each service-based stock option grant

	Year Ended December 31,
Service-Based Stock Options	2014	2013	2012
Expected dividend rate	0%	0%	0%
Expected stock price volatility	82.4% - 88.2%	74.0% – 87.9%	73.9% – 79.1%
Risk-free interest rate	1.66% - 2.2%	0.1% – 2.1%	0.9% – 1.5%
Expected life (years)	5.5 – 6.3	5.0 – 6.3	5.5 – 6.3

Summary of activity for service-based stock options

Service-Based Stock Options	Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at December 31, 2011	403,984		$	47.60	8.4	$	674,000
Granted	273,372		$	44.20
Exercised	(7,208	)	$	29.60		$	52,000
Cancelled	(52,885	)	$	40.60
Forfeited or expired	(117,889	)	$	43.60
Outstanding at December 31, 2012	499,374		$	47.60	7.5	$	—
Granted	75,751		$	21.32
Exercised	—		$	—		$	—
Expired	(164,189	)	$	51.76
Forfeited	(113,076	)	$	45.38
Outstanding at December 31, 2013	297,860		$	39.53	7.9	$	—
Granted	242,025		$	3.91
Exercised	—		$	—		$	—
Expired	(32,012	)	$	42.63
Forfeited	(30,347	)	$	32.13
Outstanding at December 31, 2014	477,530		$	21.74	8.0	$	—
Exercisable at December 31, 2014	209,375		$	36.43	6.9	$	—

Net Loss Per Common Share (Tables)

12 Months Ended

Dec. 31, 2014

Net Loss Per Common Share

Schedule of net loss attributable to common shareholders and share data used in the basic and diluted earnings per share computations using the two class method

	Year Ended December 31,
(Amounts in thousands, except per share amounts)	2014			2013			2012
Numerator:
Net loss	$	(19,920	)	$	(15,622	)	$	(29,474	)
Less: earnings attributable to convertible preferred stock	6,005			5,352			3,993
Numerator of basic and diluted EPS	$	(25,925	)	$	(20,974	)	$	(33,467	)

Denominator:
Denominator for basic and diluted EPS: weighted- average common shares outstanding	11,642			3,016			2,060
Net loss per share attributable to common shareholders (basic and diluted)	$	(2.23	)	$	(6.95	)	$	(16.25	)

Stock Purchase Warrants (Tables)

12 Months Ended

Dec. 31, 2014

Stock Purchase Warrants

Schedule of warrants outstanding

	January 2010 Class A Warrants		December 2010 Warrants		August 2013 Warrants
Exercise price	$	7.86	$	2.55	$	4.80
Expiration date	July 21, 2015		December 15, 2015		August 16, 2018
Total shares issuable on exercise	226,299		15,405		724,950

Schedule of assumptions used in calculating estimated fair value of warrants

January 2010 Class A Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	45.1		%	84.6		%
Risk-free interest rate	0.1		%	0.3		%
Expected life (years)	0.55			1.50

December 2010 Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	99.7		%	80.4		%
Risk-free interest rate	0.2		%	0.4		%
Expected life (years)	0.96			1.96

August 2013 Warrants	December 31, 2014			December 31, 2013
Closing stock price	$	3.04		$	3.23
Expected dividend rate	0		%	0		%
Expected stock price volatility	83.2		%	77.5		%
Risk-free interest rate	1.2		%	1.6		%
Expected life (years)	3.63			4.63

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References+ Details

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Measurements

Summary of valuation of the Company's investments and financial instruments that are measured at fair value on a recurring basis

	December 31, 2014								December 31, 2013
	Fair value measurement category								Fair value measurement category
(In thousands)	Total		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3
Liabilities:
Warrant liabilities	$	1,081	$	—	$	1,061	$	20	$	2,019	$	—	$	1,934	$	85

Summary of change in estimated fair values of warrant liabilities

Warrant Liabilities (In thousands)
Balance at December 31, 2012	$	1,995
Warrant issuance	5,874
Warrant exercises	(513		)
Decrease in fair value	(5,337		)
Balance at December 31, 2013	2,019
Warrant issuance	—
Warrant exercises	(965		)
Increase in fair value	27
Balance at December 31, 2014	$	1,081

Schedule of reconciliation of beginning and ending balances for the Company's fair value measurements using Level 3 inputs

	Year Ended
(In thousands)	December 31, 2014			December 31, 2013
Beginning balance	$	85		$	1,995
Decrease in fair value	(65		)	(1,910		)
Ending balance	$	20		$	85

- Definition

Tabular disclosure of liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.

+ References+ Details

- Definition

Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.

+ References+ Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Taxes

Summary of income (loss) before income taxes for U.S. and non-U.S. operations

	Year Ended December 31,
	2014			2013			2012
U.S. loss	$	(18,078	)	$	(15,622	)	$	(29,474	)
Non U.S. loss	(1,842		)	—			—
	$	(19,920	)	$	(15,622	)	$	(29,474	)

Schedule of reconciliation of income taxes computed using the federal statutory rate to the taxes reported in consolidated statements of operations

	Year Ended December 31,
(In thousands)	2014			2013			2012
Loss before income taxes	$	19,920		$	15,622		$	29,474
Federal statutory rate	34		%	34		%	34		%
Taxes computed at federal statutory rate	(6,773		)	(5,311		)	(10,021		)
State taxes (net of federal benefit)	(463		)	—			—
Warrants	(10		)	(1,815		)	(1,445		)
Nondeductible stock compensation	48			81			872
Michigan NOL benefit	—			(791		)	(1,229		)
Net operating loss expirations	655			612			612
Write-off of Section 382 limited NOL’s	67,781			—			—
Write-off of Section 383 limited R&D credits	1,600			—			—
Other	352			(27		)	300
Change in valuation allowance	(63,190		)	7,251			10,911
Reported income taxes	$	—		$	—		$	—

Schedule of deferred tax assets

	Year Ended December 31,
(In thousands)	2014			2013
Net operating loss carryforwards	$	7,092		$	70,738
Research and development credit carryforwards	—			1,600
Employee benefits and stock compensation	1,897			1,655
Research and development costs	2,184			—
Fixed assets	254			—
Intangible assets	(510		)	—
Asset Retirement obligation	127			—
Other, net	301			524
Total deferred tax assets	11,345			74,517
Valuation allowance	(11,345		)	(74,517		)
Net deferred tax assets	$	—		$	—

Schedule of reconciliation of uncertain tax provision

	Unrecognized Income Tax
(In thousands)	Benefits
Balance at December 31, 2012	$	2,100
Decrease in prior year tax positions	(1,200		)
Balance at December 31, 2013	900
Decrease in prior year tax positions	(900		)
Balance at December 31, 2014	$	—

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies

Schedule of future minimum payments related to leases

As of December 31, 2014, future minimum payments related to Vericel’s operating and capital leases are as follows:

			Payments Due by Period
Contractual Obligations	Total		2015		2016		2017		2018		More than 5 Years
Operating leases	$	9,809	$	4,215	$	4,023	$	1,323	$	248	$	—
Capital leases	152		43		43		43		23		—
Total	$	9,961	$	4,258	$	4,066	$	1,366	$	271	$	—

Acquisitions (Details) (USD $)	3 Months Ended	12 Months Ended	0 Months Ended	7 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended
Acquisitions (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2014	May 30, 2014 CTRM Business	Dec. 31, 2014 CTRM Business	Dec. 31, 2014 CTRM Business	Dec. 31, 2013 CTRM Business	May 30, 2014 CTRM Business patent	May 30, 2014 CTRM Business Sanofi Denmark	Dec. 31, 2014 CTRM Business Genzyme Biosurgery ApS Denmark	May 30, 2014 CTRM Business Commercial rights	May 30, 2014 CTRM Business Commercial rights
Acquisitions
Number of patents and patents applications acquired							250
Total purchase price consideration
Cash payment			$ 4,000,000
Promissory note			2,500,000
Total acquisition consideration			6,500,000
Total purchase price allocation
Cash							5,050,000
Accounts receivable							53,000
Inventory							2,039,000
Other current assets							192,000
Accounts payable and accrued expenses							(939,000)
Asset retirement obligation		(348,000)		(300,000)	(300,000)		(1,600,000)
Property and equipment							1,818,000
Intangible assets							3,360,000				3,400,000
Bargain purchase gain		(3,473,000)	(3,473,000)
Total consideration							6,500,000
Identifiable intangible assets acquired and their estimated useful lives
Useful Life										12 years
Unaudited pro forma condensed combined statements
Pro forma revenue					44,794,000	43,863,000
Pro forma net loss					(26,106,000)	(49,124,000)
Pro forma net loss per share - basic (in dollars per share)					$ (2.77)	$ (18.06)
Pro forma net loss per share - diluted (in dollars per share)					$ (2.77)	$ (18.06)
Cash received in order to fund the restructuring of the Denmark operations and close the facility								5,000,000
Revenue				28,400,000
Net income				1,400,000
Restructuring charge	400,000	3,000,000		3,000,000
Other expenses									$ 400,000

Restructuring (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2014	Jun. 30, 2014 employee	Dec. 31, 2013
Restructuring
Number of full time employee positions eliminated			80
Percentage of full time employee positions eliminated			30.00%
Restructuring charge	$ 0.4	$ 3.0
Restructuring reserve related to severance payments		0		0.1
Cost of product sales
Restructuring
Restructuring charge		2.5
Selling, general and administrative expenses
Restructuring
Restructuring charge		$ 0.5

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References+ Details

Selected Balance Sheet Components (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Inventory:
Raw materials	$ 1,078
Work-in-process	458
Finished goods	384
Inventory	1,920
Accounts receivable, net:
Less: Allowance for doubtful accounts	$ (40)

Selected Balance Sheet Components (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property and equipment, net:
Total property and equipment, gross	$ 7,289	$ 4,826
Less: Accumulated amortization	(4,397)	(4,087)
Total, net	2,892	739
Depreciation expense	752	489	649
Machinery and equipment
Property and equipment, net:
Total property and equipment, gross	3,135	2,547
Furniture, fixtures and office equipment
Property and equipment, net:
Total property and equipment, gross	777	761
Computer equipment and software
Property and equipment, net:
Total property and equipment, gross	667	500
Leasehold improvements
Property and equipment, net:
Total property and equipment, gross	1,691	1,018
Construction in progress
Property and equipment, net:
Total property and equipment, gross	$ 1,019

Selected Balance Sheet Components (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Intangible assets, net
Net Amount	$ 3,197
Amortization expense	200	0
Estimated future amortization expense
2015	280
2016	280
2017	280
2018	280
2019	280
Thereafter	1,797
Net Amount	3,197
Commercial rights
Intangible assets, net
Gross Amount	3,360
Accumulated Amortization	(163)
Net Amount	3,197
Estimated future amortization expense
Net Amount	$ 3,197

Selected Balance Sheet Components (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accrued expenses
Bonus	$ 2,044	$ 387
Employee related accruals	1,281	233
Accrued expenses	605
Asset retirement obligation	348
Other	436
Total	$ 4,714	$ 620

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References+ Details

Selected Balance Sheet Components (Details 5) (USD $)	Dec. 31, 2014	Sep. 30, 2014	May 30, 2014
Asset retirement obligation
Asset retirement obligation	$ 348,000
CTRM Business
Asset retirement obligation
Asset retirement obligation acquired		1,600,000
Asset retirement obligation	$ 300,000		$ 1,600,000

Stock-Based Compensation (Details) (USD $)	12 Months Ended
Stock-Based Compensation (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
2009 Plan
Stock-Based Compensation
Awards available for future grant under the Plan (in shares)	4,011,608
2004, 2001 and 1992 PLANS
Stock-Based Compensation
Awards available for future grant under the Plan (in shares)	0
Service-based stock options
Stock-Based Compensation
Weighted average grant-date fair value (in dollars per share)	$ 2.85	$ 14.07	$ 24.00
Net compensation expense related to employees and directors (in dollars)	$ 800,000	$ 900,000	$ 3,600,000
Weighted average assumptions used to estimate fair value of each service-based stock option grant
Expected dividend rate (as a percent)	0.00%	0.00%	0.00%
Options
Outstanding at the beginning of the period (in shares)	297,860	499,374	403,984
Granted (in shares)	242,025	75,751	273,372
Exercised (in shares)			(7,208)
Expired (in shares)	(32,012)	(164,189)
Cancelled (in shares)			(52,885)
Forfeited or expired (in shares)		(113,076)	(117,889)
Forfeited (in shares)	(30,347)
Outstanding at the end of the period (in shares)	477,530	297,860	499,374	403,984
Exercisable at the end of the period (in shares)	209,375
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 39.53	$ 47.60	$ 47.60
Granted (in dollars per share)	$ 3.91	$ 21.32	$ 44.20
Exercised (in dollars per share)			$ 29.60
Expired (in dollars per share)	$ 42.63	$ 51.76
Cancelled (in dollars per share)			$ 40.60
Forfeited or expired (in dollars per share)		$ 45.38	$ 43.60
Forfeited (in dollars per share)	$ 32.13
Outstanding at the end of the period (in dollars per share)	$ 21.74	$ 39.53	$ 47.60	$ 47.60
Exercisable at the end of the period (in dollars per share)	$ 36.43
Weighted Average Remaining Contractual Term (Years)
Outstanding at the beginning of the period	8 years	7 years 10 months 24 days	7 years 6 months	8 years 4 months 24 days
Outstanding at the end of the period	8 years	7 years 10 months 24 days	7 years 6 months	8 years 4 months 24 days
Exercisable at the end of the period	6 years 10 months 24 days
Aggregate Intrinsic Value
Outstanding at the end of the period				674,000
Exercised			52,000
Additional disclosures
Total unrecognized compensation cost (in dollars)	800,000
Weighted average period over which unrecognized compensation is expected to be recognized	2 years 9 months 26 days
Total fair value of options vested (in dollars)	$ 1,500,000	$ 2,300,000	$ 3,000,000
Service-based stock options \| Minimum
Weighted average assumptions used to estimate fair value of each service-based stock option grant
Expected stock price volatility (as a percent)	82.40%	74.00%	73.90%
Risk-free interest rate (as a percent)	1.66%	0.10%	0.90%
Expected life	5 years 6 months	5 years	5 years 6 months
Service-based stock options \| Maximum
Weighted average assumptions used to estimate fair value of each service-based stock option grant
Expected stock price volatility (as a percent)	88.20%	87.90%	79.10%
Risk-free interest rate (as a percent)	2.20%	2.10%	1.50%
Expected life	6 years 3 months 18 days	6 years 3 months 18 days	6 years 3 months 18 days
Service-based stock options \| Non-employee
Stock-Based Compensation
Vesting period	1 year
Service-based stock options \| 2009 Plan
Stock-Based Compensation
Expiration period	10 years
Vesting period	4 years

Shareholders' Equity (Details) (USD $)	0 Months Ended		12 Months Ended	309 Months Ended		0 Months Ended	12 Months Ended			0 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended		12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended
Shareholders' Equity (Details) (USD $)	Sep. 17, 2014	Aug. 16, 2013	Dec. 31, 2013	Dec. 31, 2014	Sep. 17, 2014	Aug. 16, 2013 Common Stock	Dec. 31, 2014 Common Stock	Dec. 31, 2013 Common Stock	Aug. 16, 2013 Common Stock	Aug. 16, 2013 Warrants	Aug. 16, 2013 Warrants	Jun. 16, 2011 MLV	Dec. 31, 2014 MLV	Dec. 31, 2013 MLV	Jun. 16, 2011 Maximum MLV	Jan. 21, 2014 Lincoln Park	Dec. 31, 2014 Lincoln Park	Jan. 21, 2014 Lincoln Park	Jan. 21, 2014 Lincoln Park Minimum	Jan. 21, 2014 Lincoln Park Maximum	Dec. 31, 2014 Lincoln Park Maximum	Sep. 07, 2014 August 2013 warrants item	Jul. 09, 2014 August 2013 warrants	Dec. 31, 2014 August 2013 warrants	Jul. 09, 2014 August 2013 warrants	Dec. 31, 2013 August 2013 warrants
Shareholders' Equity
Issuance of common stock, net of issuance costs of $3,167 and $980 for 2014 and 2013, respectively (in shares)	15,784,313					1,500,000	18,655,000	2,153,000
Offering price (in dollars per share)					$ 2.55				$ 6.00															$ 3.04		$ 3.23
Number of warrant holders																						1
Number of shares purchased on exercise of warrants											1,500,000													724,950	362,500
Common stock, par value (in dollars per share)			$ 0	$ 0																					$ 0
Stock Issued to Underwriter for Exercise of Over Allotment Option						50,000
Class of Warrant or Right Warrants Issued to Underwriter for Exercise of Over Allotment Option											50,000
Exercise price of warrants (in dollars per share)											$ 6.00													$ 4.80	$ 4.80
Proceeds from issuance of common stock	$ 37,500,000	$ 8,200,000											$ 7,100,000	$ 4,800,000			$ 3,700,000
Fair market value of the warrants			5,874,000							5,900,000
Issuance cost	300,000
Net proceeds from exercise of warrants																							1,500,000
Value of shares of common stock to be sold																				15,000,000
Value of remaining shares of common stock to be sold																	11,300,000
Period over which shares of common stock to be purchased																30 months
Number of shares of common stock to be purchased in regular purchases																				50,000
Number of shares of common stock to be purchased depending upon the closing sale price of the common stock																				100,000
Threshold closing sale price of the common stock on the date of a regular purchase to trigger purchase of additional amounts as accelerated purchases (in dollars per share)																			$ 3.00
Period of business days over which purchase price of shares of common stock will be determined																				10 days
Floor price for sale of shares of common stock (in dollars per share)																		$ 2.50
Threshold on percentage of outstanding shares of the common stock that can be beneficially owned by counterparty																					9.99%
Number of shares of common stock sold			4,723,000	23,786,000													935,499,000
Amount of net capacity remaining on the ATM													7,800,000
Underwriter's discount	2,400,000
Expected proceeds from sale of common stock															20,300,000
Percentage of gross proceeds payable as commission												3.00%
Cash dividends declared and paid				$ 0

Net Loss Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net loss	$ (19,920)	$ (15,622)	$ (29,474)
Less: dividends accumulated on convertible preferred stock	6,005	5,352	3,993
Numerator of basic and diluted EPS	$ 25,925	$ 20,974	$ 33,467
Denominator for basic and diluted EPS:
Weighted-average common shares outstanding	11,642,000	3,016,000	2,060,000
Net loss per share attributable to common shareholders (basic and diluted) (in dollars per share)	$ (2.23)	$ (6.95)	$ (16.25)
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share	2,300,000	2,400,000	1,400,000

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References+ Details

Stock Purchase Warrants (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 17, 2014	Dec. 31, 2014 January 2010 Class A Warrants	Dec. 31, 2013 January 2010 Class A Warrants	Dec. 31, 2014 December 2010 Warrants	Dec. 31, 2013 December 2010 Warrants	Dec. 31, 2014 August 2013 warrants	Dec. 31, 2013 August 2013 warrants	Jul. 09, 2014 August 2013 warrants
Stock Purchase Warrants
Exercise price per share (in dollars per share)					$ 7.86		$ 2.55		$ 4.80		$ 4.80
Total shares issuable on exercise					226,299		15,405		724,950		362,500
Assumptions used in calculating the estimated fair value of the warrants
Closing stock price (in dollars per share)				$ 2.55	$ 3.04	$ 3.23	$ 3.04	$ 3.23	$ 3.04	$ 3.23
Expected dividend rate (as a percent)					0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Expected stock price volatility (as a percent)					45.10%	84.60%	99.70%	80.40%	83.20%	77.50%
Risk-free interest rate (as a percent)					0.10%	0.30%	0.20%	0.40%	1.20%	1.60%
Expected life					6 months 18 days	1 year 6 months	11 months 16 days	1 year 11 months 16 days	3 years 7 months 17 days	4 years 7 months 17 days
Balance at the beginning of the period	$ 2,019	$ 1,995
Warrant issuance		5,874
Warrant exercise	(965)	(513)
Decrease in fair value	27	(5,337)	(4,248)
Balance at the end of the period	$ 1,081	$ 2,019	$ 1,995

Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	$ 1,081	$ 2,019	$ 1,995
Change in the estimated fair value of warrant liabilities
Balance at the beginning of the period	2,019	1,995
Warrant issuance		5,874
Warrant exercise	(965)	(513)
Decrease in fair value	27	(5,337)	(4,248)
Balance at the end of the period	1,081	2,019	1,995
Level 2
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	1,061	1,934
Change in the estimated fair value of warrant liabilities
Balance at the end of the period	1,061	1,934
Level 3
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	20	85
Change in the estimated fair value of warrant liabilities
Balance at the end of the period	$ 20	$ 85

Fair Value Measurements (Details 2) (Level 3, Warrants, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Level 3 \| Warrants
Reconciliation of beginning and ending balances for the company's fair value measurements using Level 3 inputs
Beginning balance	$ 85	$ 1,995
Decrease in fair value	(65)	(1,910)
Ending balance	$ 20	$ 85

Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of income taxes computed using the federal statutory rate to the taxes reported in consolidated statements of operations
Loss before income taxes	$ 19,920	$ 15,622	$ 29,474
Federal statutory rate (as a percent)	34.00%	34.00%	34.00%
Taxes computed at federal statutory rate	(6,773)	(5,311)	(10,021)
State taxes (net of federal benefit)	(463)
Warrants	(10)	(1,815)	(1,445)
Nondeductible stock compensation	48	81	872
Michigan NOL benefit		(791)	(1,229)
Net operating loss expirations	655	612	612
Write-off of Section 382 limited NOL's	67,781
Write-off of Section 383 limited R&D credits	1,600
Other	352	(27)	300
Change in valuation allowance	(63,190)	7,251	10,911
Deferred tax assets
Net operating loss carryforwards	7,092	70,738
Research and development credit carryforwards		1,600
Employee benefits and stock compensation	1,897	1,655
Research and development costs	2,184
Fixed assets	254
Intangible assets	(510)
Asset retirement obligation	127
Other, net	301	524
Total deferred tax assets	11,345	74,517
Valuation allowance	$ (11,345)	$ (74,517)

Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	0 Months Ended
	Sep. 17, 2014	Sep. 16, 2014	Dec. 31, 2014 Federal Internal Revenue Service	Dec. 31, 2014 State
Operating loss carryforwards
Projected annual limitation on the use of the net operating losses that existed prior to September 17, 2014		$ 0.8
Net operating loss carryforwards			19.3	7.8
Decrease in net operating loss	$ 192.7

Income Taxes (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Taxes
Balance at the beginning of the period	$ 900	$ 2,100
Decrease in prior year tax positions	(900)	(1,200)
Balance at the end of the period		$ 900

Concentration of Credit (Details) (Revenue, Customer concentration)	12 Months Ended
	Dec. 31, 2014
One distributor in the U.S
CONCENTRATION
Concentration risk (as a percent)	76.00%
One customer
CONCENTRATION
Concentration risk (as a percent)	10.00%

Commitments and Contingencies (Details) (USD $)	12 Months Ended
Commitments and Contingencies (Details) (USD $)	Dec. 31, 1992 University Of Michigan	Dec. 31, 2014 Corning	Dec. 31, 2014 Corning Maximum
Licenses, Royalties and Collaborative Agreements and Commitments
Royalty revenue as a percentage of net sales of products	2.00%	5.00%
Future royalty revenue			$ 50,000,000

Commitments and Contingencies (Details 2)	12 Months Ended
Commitments and Contingencies (Details 2)	Dec. 31, 2014 item
Ann Arbor, Michigan
Operating Leases
Lease term	5 years
Market value renewal options, number	2
Market value renewal option term	5 years
Cambridge, Massachusetts
Operating Leases
Market value renewal options, number	2
Market value renewal option term	3 years

Commitments and Contingencies (Details 3) (USD $)	12 Months Ended
Commitments and Contingencies (Details 3) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating leases
2015	$ 4,215,000
2016	4,023,000
2017	1,323,000
2018	248,000
Total	9,809,000
Capital leases
2015	43,000
2016	43,000
2017	43,000
2018	23,000
Total	152,000
Operating and capital leases
2015	4,258,000
2016	4,066,000
2017	1,366,000
2018	271,000
Total operating and capital leases	9,961,000
Rent expense	$ 2,500,000	$ 1,000,000	$ 1,100,000

Preferred Stock (Details) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended
Preferred Stock (Details) (USD $)	Aug. 15, 2011 Right	Oct. 31, 2013 Right	Mar. 31, 2012 Eastern Capital Limited and its affiliates Maximum	Dec. 31, 2014 Series A Junior Participating Cumulative Preferred Stock	Dec. 31, 2014 Series A Junior Participating Cumulative Preferred Stock Minimum
Shareholder Rights Plan
Percentage of common stock approved to be purchased			49.90%
Number of rights for each outstanding share of common stock	1	20
Additional number of rights per common share	1
Number of rights deemed to be delivered for each share of common stock issued or transferred		20
Number of shares purchased on exercise of warrants				0.0001
Par value per share (in dollars per share)				$ 0
Exercise price per share (in dollars per share)				$ 30.00
Preferred stock, shares authorized				45,000
Preferred stock, shares issued				0
Preferred stock, shares outstanding				0
Percentage of common stock to be acquired for rights to be exercisable by an individual or group					15.00%
Percentage of common stock to be owned for rights to be exercisable by an individual or group commencing a tender offer					15.00%
Multiple of the value of common stock acquired (after conversion from preferred) to the exercise price of stock purchase right in the event of an acquiring person event				2
Multiple of the value of common stock acquired to the exercise price of stock purchase right in the event of a merger of the entity				2
Redemption price per right (in dollars per right)				$ 0.001

Preferred Stock (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		12 Months Ended	0 Months Ended
	Sep. 17, 2014	Aug. 12, 2013 Series B voting convertible preferred stock	Dec. 31, 2014 Series B voting convertible preferred stock	Aug. 12, 2013 Series B-1 non-voting convertible preferred stock	Mar. 09, 2012 Series B-1 non-voting convertible preferred stock	Dec. 31, 2013 Series B-1 non-voting convertible preferred stock	Aug. 12, 2013 Series B-1 non-voting convertible preferred stock
Series B Convertible Preferred Stock
Number of shares sold	15,784,313				12,308
Offering price per share (in dollars per share)					$ 3,250
Period of closing of offering after which shares are convertible			5 years	5 years
Conversion price per share (in dollars per share)			$ 3.25
Conversion ratio, the number of shares of common stock received per share of convertible preferred stock			50
Percentage of cumulative dividend rate			11.50%
Accumulated shares but undeclared dividends						235,077
Redemption price (in dollars per share)							$ 7,430
Reclassification of Series B preferred stock		$ 38.4
Period for accrual of dividend			5 years

Summary of Significant Accounting Policies (Details)	12 Months Ended
Summary of Significant Accounting Policies (Details)	Dec. 31, 2014
Equipment and computers \| Minimum
Property, Plant and Equipment
Useful lives	3 years
Equipment and computers \| Maximum
Property, Plant and Equipment
Useful lives	5 years
Furniture, fixtures and office equipment
Property, Plant and Equipment
Useful lives	5 years
Building improvements and leasehold improvements \| Maximum
Property, Plant and Equipment
Useful lives	7 years

Income Taxes (Details 3)	0 Months Ended
Income Taxes (Details 3)	Sep. 17, 2014
Income Taxes
Minimum cumulative percentage change of ownership over which change in control is considered	50.00%
Rolling period over which cumulative change of ownership is required for change in control	3 years

Organization (Details)	12 Months Ended
Organization (Details)	Dec. 31, 2014 segment	May 30, 2014 CTRM Business patent
Organization
Number of patents and patents applications acquired		250
Number of reportable segments	1

Summary of Significant Accounting Policies (Details 2) (Series B voting convertible preferred stock, USD $)	Dec. 31, 2014
Series B voting convertible preferred stock
Net Loss Per Share Attributable to Common Shareholders
Accumulated Undeclared Dividends	$ 6.0